addFilters
Description
addFilters(
imports the specified filters to the Filter Analyzer
app fa
,filt
1,...,filt
n)fa
and plots their responses in the active display. If there is
no active display, Filter Analyzer adds a new display and plots the filters on
it.
addFilters(___,
specifies additional options using name-value arguments.Name=Value
)
returns the identification number corresponding to a newly added display. If there is
already a display, Filter Analyzer returns an empty array.dispnum
= addFilters(___)
Examples
Add Filters
Design a lowpass filter and show it in the Filter Analyzer app.
d1 = designfilt("lowpassfir", ... PassbandFrequency=0.45,StopbandFrequency=0.55); fa = filterAnalyzer(d1,FilterNames="LP1");
Add another lowpass filter to the display.
d2 = designfilt("lowpassfir", ... PassbandFrequency=0.25,StopbandFrequency=0.35); addFilters(fa,d2,FilterNames="LP2");
Input Arguments
fa
— Filter Analyzer app handle
filterAnalyzer
object
Filter Analyzer app handle, specified as a filterAnalyzer
object.
filt
— Input filter
coefficient matrices | cell array | digitalFilter
object | filter System object™
Input filter, specified as coefficient matrices, a cell array, a
digitalFilter
object, or a filter
System object.
For more information, see Import
Filter
.
Example: b = [1 3 3 1]/6
and a = [3 0 1 0]/3
together specify a third-order lowpass Butterworth filter with a normalized 3-dB
frequency of 0.5π rad/sample.
Example: sos2ctf([2 4 2 6 0 2; 3 3 0 6 0 0])
specifies a
third-order lowpass Butterworth filter with a normalized 3-dB frequency of
0.5π rad/sample.
Example: d =
designfilt("lowpassiir",FilterOrder=3,HalfPowerFrequency=0.5)
specifies
a third-order lowpass Butterworth filter with a normalized 3-dB frequency of
0.5π rad/sample.
Example: hd =
design(fdesign.lowpass,"butter",SystemObject=true)
specifies a lowpass
Butterworth filter System object.
Filter Coefficients
You can use Filter Analyzer to analyze filters specified as numerator and denominator coefficients. If you specify the coefficients as the K-row matrices
Signal Analyzer assumes you have specified the filter as a sequence of K cascaded transfer functions (CTF) such that the full transfer function of the filter is
where m ≥ 0 is the numerator order of the filter and n ≥ 0 is the denominator order.
If K = 1, then B and A are row vectors that specify the transfer function of an IIR filter.
If you specify both B and A as column vectors, Filter Analyzer assumes they represent the transfer function of an IIR filter.
If B is a scalar, Filter Analyzer assumes you specified the filter as a cascade of all-pole IIR filters with each section having a scaling gain equal to B.
If A is a scalar, Filter Analyzer assumes you specified the filter as a cascade of FIR filters with each section having a scaling gain equal to 1/A.
Note
Coefficients and Gain
If you have a scaling gain separate from the coefficient values, you can enter it
in Filter Analyzer using the Import Filter dialog
box. At the command line, you can specify the coefficients and gain as a cell array
of the form {B,A,g}
, where B and A are as
previously defined.
The gain can be a scalar overall gain or a vector of section gains.
If the gain is a scalar, Filter Analyzer applies the value uniformly to all the cascade filter sections.
If the gain is a vector, it must have one more element than the number of filter sections in the cascade. Filter Analyzer applies a scale value to each of the filter sections and applies the last value uniformly to all the filter sections.
If you specify the coefficient matrices and gain vector as
Signal Analyzer uses the transfer function
digitalFilter
Objects
You can use Filter Analyzer to analyze digitalFilter
objects. Use designfilt
to generate or edit digital filters based on
frequency-response specifications.
Filter System Objects
If you have DSP System Toolbox™, you can use Filter Analyzer to analyze these filter System objects.
System object |
---|
dsp.AllpassFilter |
dsp.AllpoleFilter |
dsp.BiquadFilter |
dsp.CICCompensationDecimator |
dsp.CICCompensationInterpolator |
dsp.CICDecimator |
dsp.CICInterpolator |
dsp.CoupledAllpassFilter |
dsp.Delay |
dsp.Differentiator |
dsp.DigitalDownConverter |
dsp.DigitalUpConverter |
dsp.FIRDecimator |
dsp.FIRFilter |
dsp.FIRHalfbandDecimator |
dsp.FIRHalfbandInterpolator |
dsp.FIRInterpolator |
dsp.FIRRateConverter |
dsp.FarrowRateConverter |
dsp.FilterCascade |
dsp.FourthOrderSectionFilter — Filter
Analyzer does not support fixed-point arithmetic for
this object |
dsp.HighpassFilter |
dsp.IIRFilter |
dsp.IIRHalfbandDecimator |
dsp.IIRHalfbandInterpolator |
dsp.LowpassFilter |
dsp.NotchPeakFilter
— Filter Analyzer does not support fixed-point
arithmetic for this System object |
dsp.ParallelFilter |
dsp.SOSFilter |
dsp.VariableBandwidthFIRFilter |
dsp.VariableBandwidthIIRFilter |
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| cell
Complex Number Support: Yes
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: FilterNames=["LP" "HP"],SampleRates=[150
3e3]
Arithmetic
— Arithmetic type of filter System objects
"double"
(default) | "single"
| "fixed"
Arithmetic type of filter System objects, specified as one of
"double"
, "single"
, or
"fixed"
. If you do not specify this argument, and the filter
System objects are in an unlocked state, Filter Analyzer assumes the filters
are double precision.
Data Types: char
| string
DisplayNums
— Displays to plot filters
vector
Displays to plot filters, specified as a vector of display numbers. If you do not specify this argument, Filter Analyzer uses the active display. Use display identification numbers to target displays when using other Filter Analyzer functions. Identification numbers appear above the plotting area of the app, on the tabs that correspond to the different displays.
Example: [1 4]
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
FilterNames
— Filter names
string vector
Filter names, specified as a string vector. Filter names are the names that identify the different filters in the app Filters table. If you do not specify this argument:
If filters are specified as numerator and denominator coefficients, Filter Analyzer uses
num_den
as filter names, wherenum
is the variable that specifies the numerator coefficients of a filter andden
is the variable that specifies the corresponding denominator coefficients.If filters are specified as cell arrays or objects, Filter Analyzer uses as filter names the variables that specify each cell array or object.
Otherwise, Filter Analyzer uses names consisting of
Filter_
plus a number:Filter_1
,Filter_2
, and so on.
Filter names in Filter Analyzer must be unique. If a name already exists, the app appends a suffix number to the name. The Filters table shows the names that already exist in the app session.
Example: ["LPbutter" "LPelliptic"]
Data Types: char
| string
SampleRates
— Filter sample rates
1 (default) | scalar | vector
Filter sample rates, specified as a scalar or vector of values specified in Hz.
If
SampleRates
is a scalar, the specified value applies to all filters.If
SampleRates
is a vector, it must have a number of elements equal to the number of filters.
This argument does not apply if one or more filters are objects with a sample rate.
Example: [150 3e3]
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Output Arguments
dispnum
— Display identification number
integer | vector of integers
Display identification number. If more than one display is added,
dispnum
is a vector. If Filter Analyzer uses the
current display, dispnum
is an empty array.
Version History
Introduced in R2024a
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